Abstract:

Nanostructured thin film of cobalt supported on glassy carbon (nm-Co/GC) was prepared by electrochemical deposition under cyclic voltammetric conditions. SEM studies illustrated that the Co film was composed of most irregularly small Co nanoparticles with an average size of 150 nm and a few large Co particles of diameter ranging from 400 nm to 500 nm. In situ FTIR spectroscopy employing CO adsorption as the probe reaction revealed that the nanostructured Co film exhibited abnormal infrared effects. The unique anomalous IR features of CO adsorbed on nm-Co/GC consist of the inversion of the CO_ad IR bands, the significant enhancement of IR absorption of CO_ad, and the large Stark effect as well as broadening of the CO_ad IR bands (the FWHM of CO_L on nm-Co/GC is 8 cm^-1 larger than that on bulk Co). The current investigation can extend the study of AIREs to nanomaterials of metals of iron family, and gain an insight into the origin of particular properties of nanomaterials.

Key words: Nanostructured Co thin film, Abnormal infrared effect, In situ FTIRS, Electrodeposition